Puking/spitting up milk

Hi there!

I'm lowkey worried about my almost 9mo old's puking/spitting up milk.

It's only milk, I rarely have him spitting up solids or purees.

Lately I really noticed it's more than usual.

Update ;

Oh I should mention it's his formula, he's had that the last 9 months (this specific age variant for the last 3 months)

He drinks it but then it comes out between 30 minutes up to 3 hours after he's eaten, so it's not for not wanting it.